The need to accurately hit a target on the first shot has become increasingly important for marksmen in the field, as a marksman may be responsible for an area of surveillance with a radius of up to 3000 meters. To achieve long range shots of upwards of 1000 meters or more, marksmen must calculate the settings that need to be dialed into a firearm scope to ensure that there is a high probability of hit on the intended target. The marksman typically uses a ballistics device to calculate the settings needed on the firearm scope for the intended impact point. The ballistics device uses a ballistics algorithm which integrates all present variables, such as range to target, slant angle, wind, temperature, altitude, humidity, barometric pressure, position on earth, etc. These variables are integrated against an assumed projectile (i.e. bullet) muzzle velocity for the particular projectile and firearm that the marksman is using. Projectile muzzle velocity is generally provided as a constant from the manufacturer of the projectile. Although every effort may be taken in the production of the bullets to produce a repeatable product with the same muzzle velocity, the actual muzzle velocity when the marksman is in the field is usually different. In fact, bullets from even the same processing batch can have muzzle velocities that differ by 5-10% depending on the conditions and manufacturing tolerances. Errors in the projectile muzzle velocity can have a significant impact on the error in the calculated impact point. Projectile muzzle velocity is the initial variable in a ballistics equation, so any error in the muzzle velocity will be amplified throughout the calculation, the error exponentially growing with an increase in target range.
While muzzle velocities may be measured in a controlled environment, such as a laboratory or a controlled range, these measured velocities may be unreliable in the field, where conditions are continually changing. Certain technologies currently exist to accurately measure the actual muzzle velocity of a projectile while in the field. However, the existing technology is impractical to use in field operations, requiring bulky and cumbersome equipment, changes to the projectile itself, and/or changes to the barrel of the firearm. For example, a chronograph may be used to measure the actual muzzle velocity. However, such devices are impractical for field operations because they require the marksman to fire through a large device placed in front of the firearm, preventing the marksman from remaining hidden.
Another existing technology, such as that disclosed in U.S. Pat. No. 4,483,190, uses sensors positioned adjacent to the path of a projectile containing magnetic material, the sensors being able to measure the magnetic field as the projectile leaves the muzzle in order to determine the muzzle velocity. However, this requires modification to the projectile itself, possibly changing certain projectile manufacturer specifications given.
Similarly, U.S. Pat. No. 6,064,196 discloses technology for measuring muzzle velocity. However, the technology requires a magnet to be placed on the projectile body. Additionally, the technology requires a sensor to be placed inside the muzzle, thereby altering the original characteristics of the firearm. Thus, there is a need for technology which accurately and efficiently calculates projectile muzzle velocity in the field without having to modify the projectile or the firearm.
Embodiments of the technology disclosed herein address these and other problems individually and collectively.